Saturday, September 30, 2006

Away from the Lawn - Columbia University

Away from the lawn, sans scope, I participated as a pedestrian to Columbia University's Astronomy and Astrophysics department public outreach. Two grad students, Cameron & Neil, tended to 2 ~ 3 dozen people, including a film crew that was shooting on the 13th & 14th floor, who came up to the roof of Pupin Hall to look through three scopes. I suspect that there was a third host because there were three scopes altogether but if there was I missed to meet him or her. Both Cameron & Neil obviously enjoyed what they were doing by sharing their knowledge of the heavens, describing their grad work, and gracefully deflecting conversations about UFOs.

If the weather and your schedule permit, I strongly recommend dropping in on one of the Fall public observing sessions. It's worthwhile to have three large scopes, two domes, and friendly persons providing facts and viewing of astronomical wonders. One can sign upon their mailing list to receive alerts. Check it out on the public outreach page, the "Open Nights" tab seen in the middle of the page.

September 22October 20November 17December 15

This was my very first time observing from within a dome. These structures are worth their weight in gold since they do a fantastic job ridding all the ambient light except that which comes in through the slit of the dome. Local, ambient light can severely limit how dim one can see and it is a nuisance causing glare in the eyepiece. Also, one can't feel like you're not doing atsronomy as well as twist of romaticism to add.

I could make it a habit to abandon TotL and make Pupin Hall our new observatory. Now only have to find money for new eyepieces and tuition.

These past two evenings offered tremendously transparent skies. The second evening had bothersome clouds but the sky was still phenomenal. It felt at times that when we selected a clear patch the clouds would move in - naturally.

The first evening I observed solo and felt like I was able to cover a lot in the little time that I was there. Not many persons passed by. The world around me literally melted away while my attention was captured in easy celestial hunts and treasures unearthed.

I wanted to test ride the Takahashi bins. I read a few reviews and was intent on performing some tests to get an idea of how well they perform. On my ride up to the park I began to write out a battery of tests, but in actuality I shared time between observing, sketching, and testing.

Although sky conditions calculate into limiting magnitude, I selected NGC225 to conduct a test. I was able to see as dim magnitude 10.3. This cluster has an diamond-shaped arrangement of stars inside of greater perimeter of stars which I was unable to see. For the ambitious, if you go to the scanned map at WebDA , star number 9 was dimmest star I could resolve, number 10 the brightest of the interior diamond, which I didn't see, is magnitude 10.6.

Next item that I wanted to test was resolution, so I chose a number of doubles to get an idea of unequal brightness and separation values. On the second night I revisited these to get Charlie's impression. I believe we both agreed on resolving but had different impressions ofSTF 205 A-BC (gamma And, Almach)m: 2.31/ 5.02 1779: 9.3"/ 70° 2003: 9.5"/ 63°could not resolve, suspected unequal secondary WNW to primary

Another aspect of the binocular performance was to check where starpoints began to degrade such that they were not pinpoint sharp. I asked Charlie if he could make a judgment so I could see if we agreed. He determined that stellar image of magnitude ~7.5 began to degrade about 1/6 from edge to center. I was a little less tolerant and judged it to start around 1/5 from field stop to center of field of view. Degradation was not terrible at all, just that it began to loose sharp focus.

On both evenings I covered a pretty good range of objects and sky. Solar system objects included two very easy starhops to the planets Uranus in Aquarius and Neptune in Capricorn. Both are conveniently near bright stars which stay in the field of view. Thinking back, on the second night I relied on my sketches from the night before rather than checking the atlas to make sure I was in field. Saw a few meteors each night when Auriga had risen up to 25°+.

The summer sky is on its way down by midnight, I don't see Scorpio nor Antares in the southwest. I took this opportunity to check in M13,M56, M57, Albireo, and other objects that will soon be below the horizon when it gets dark. These days time seems to fly for me so might as well check 'em out while they're still up there.

Lastly regarding the size of field of view in the Tak bins, alpha-, epsilon-, and zeta Lyr just fit to the edge of the field of view. Epsilon^2, the other double of the Double Double doesn't fit. Objects that I think frame beautifully in these bins include the Muscleman Cluster in Perseus, nearby the Double Cluster which is also a beautiful sight. Orion's belt extending from NGC1981 down to iota is another favorite.

I've yet to get these to dark skies but when I do M31, M32, & M110 will be the Top of the List.

Monday, September 25, 2006

the sky mirror in rockefeller center

I walk through Rockefeller Center twice a day most days - on my way to and on returning from work. Rockefeller Center hosts a lot of installations throughout the year. Sometimes the plaza from where this photo's eye stands is filled with television stage, art installations, rocket ships, automobiles, memorials, and Christmas trees. The alleyway seen across the sunken plaza (double duties between cafe and ice rink) is the other area where installations find themselves such as this huge Sky Mirror by Anish Kapoor and organized by Public Art Fund.

Credits to Anish Kapoor & enablers

Standing in that alleyway much closer to the Sky Mirror. This is the concave side.

Here is a view from Fifth Ave. looking west - the rear of the mirror with Rockefeller Center building towering above. Go to the Top of the Rock.

And, this is a closeup, showing a reflection on the entire backside of the mirror. This is the convex side and I am behind the flash~% D.

Charlie photographed and wrote in greater detail about this as well, check out his blog for this and more.

two worlds intersect

Just for fun - a "Moleskine notebook user" (in the most objective terms) offers eye care advice.As with most products I use, I am a brand loyalist. My log books are exclusively Moleskine notebooks. Compared with the Palm and Newton the pencil-n-paper experience provides conventional, existential pleasure - same as observational astronomy.

Friday, September 22, 2006

Like a druid drawn to Stonehenge

The autumnal equinox occurs tommorow,Sept. 23, 2006, at 12:03 A.M. EDT. However, that did not stop me, and many others, from stopping by the steel Sun Triangle to consider our local solar noon event as an indication of equinox. The large steel sculpture is a product of Athelstan Spilhaus (checkout the clock he designed) in the pit of the McGraw Hill Buildingin NYC. I arrived around twenty minutes to one and a dozen or more people were gathered by five to one, already past the local noon. And just like the solstice event earlier this year, people lined up to look directly at the sun with no protection other than some heavy squinting. For the equinox one sights along the long, top side of the triangle as opposed to the forward short side.

Charlie has a photograph he marked up showing how the sides are used with these seasonal events and has a lot of good shots & description on this page.

I thought that noon occurred at 12:50pm EDT because that's when I considered the shadow shortest. The shadow is not as crisp as I'd like it and would even say that noon occurred at 12:51 when I saw a small "notch in the shadow" that could only be seen if sunlight was aligned with it. The "notch" is created by the joint between the triangle and its base.

When the Sun does cross the celestial equator from north to south, marking of the beginning of Fall, it will be noon somewhere in the world. As someone said while pointing at the Sun Triangle, "But they don't have this."

This is an old photo of the Sun Triangle taken at the time of solstice. I forgot my camera today but Charlie had his. Stop by his blog later to see what he uploadedhis report. Compare the shadows from solstice with Charlie's photos of equinox relative to the base of the gnomon.

Okay. Some like the challenge of a par 5 with a range anywhere between 435 and 630 m (476 and 690 yds.) Me? I love the challenge of collecting photons from outer space, a range of light seconds to millions of light years. Where a golfer chooses among woods, irons, and putters to do the right job, I choose from my supply of binoculars, reflectors, and refractors, each designed with a special purpose.

The last crescent before New Moon does not require a driver. Nope we're talking the short game, a small refractor or better yet binoculars are satisfactory to catch photons that left the lunar surface about 1.35 seconds earlier. My tripod was topped with my reliable Takahashi 22x60 binoculars and Charlie had his trusty Canon 15x image stabilized bins.

The slender crescent Moon was spotted with in the handheld Fujinon 7x50 bins at 05:57:04am EDT at an elevation of 1°01'. The first image above leads to a marked up version showing where Moon rose relative to the Sun. I calibrated my watch with eBay. My watch differed from them by being fast 1m 04s so with this corrected for the timestamps in my logbook.It wasn't really difficult to predict that this crescent was going to be easy. And it was. Elongation was 10°47' and the ecliptic stood very steep so that the Sun was still well below the horizon when the Moon rose. I am surprised by the low altitudes we are able to see at. Moon's age 25h49m in terms of absolute age relative to the New Moon - pretty easy.

The crescent was "lumpy" exhibiting an uneven brightness. Two bright patches on the crescent between 5:30 and 8:30 measured along the limb were made from a darkening about 6:30~ish. These were the remarkable features that I noticed in the bins and naked eye. It was this aspect that impressed me most and exceeded that threshold of contrast that allows me to detect it. When I turned to talk to Charlie it would allow me to recover Moon from a brightening sky. The horns reached to 4:30 and 8:30 ~9:00 and with those bright patches just mentioned I could see with certainty that the crescent was tipped to our right.

It was exciting to watch the crescent until I could see it no longer. I lost it again this month by a similar action: turning away my attention at that critical end so now I know to stay in the eyepiece until I lose it from gaze not inattention. Today as I said I turned to speak to Charlie. Leading up to the time I lost it I had done the same thing a couple of times, that is taking my eyes from the bins. But each time I looked back into the EPs, I relied on establishing Venus and then looking off for the crescent. It would be a moment, my eyes adjusted, and there Moon appeared still maintaining a contrast that was good enough for me to see our neighbor. I knew these were frail moments as I appreciated this small strip around the 7:30 ~ 8:30 that would catch my eye. I see you. I thought to myself maybe this is what the record holders experience when they catch these slender crescents just barely visible - and yet they've done it without the crutch of Venus or any other nearby astronomical landmark. Bravo to them. And practice, practice, practice for me when the opportunity comes.

Wednesday, September 20, 2006

20060921 - Last Crescent Alert

A reminder that tomorrow morning the last crescent rises 05:46EDT || 09:46UT. Back in July was the last time Charlie & I caught the slender crescent rise, a report is here.

I anticipate a sighting around 6am, give or take 3 or 4minutes to either side. That July sighting we had incredibly clear horizon for a bridge top observation at 1°29'. If the same occurs on Thursday then could be slightly earlier.

Monday, September 18, 2006

It's my patch

Click thumbnail for larger field of viewI imagine that I am not unique and that many observers have a special part of the sky that they relate to more intimately than others. For me, that is the stretch of sky from the Square of Cassiopeia out to the eye of Medusa in Perseus and the moving cluster around Mirfak. This part of the sky is rich and easy to navigate. In smaller scopes or even larger scopes under urban skies, open clusters are easy pickings. True, not all clusters jump out and bite but with some knowledge, expectation setting, and coaxing these are easy grabs for the samll scope or bright urban skies. One can appreciate the diversity that each one brings to your observing experience.A host of catalogs identify a number of open clusters: Messier, Collinder, Stock, Trumpler, Dolidze, King, Basel, Czernik and more. I have mostly concentrated on NGC, Messier, Stock, and Trumpler open clusters.

I prefer to start my hop from the Square of Cassiopeia. The Square of Cassiopeia is the area of sky framed by beta-, alpha, gamma-, kappa Cas. When it is rising in the "Corridor" I can move up the sky to observe NGC 7789 on my way to M52. But tonight my first visit is NGC225. I starhop NE from gamma Cas past the mag 4.8 star leading to an arrangement of four stars that strikes me as a "pinwheel", this points right into NGC225. I'll use the pinwheel in the eyepiece coupled with NGC225 to establish an orientation which I can hop with ease to Stock24 and NGC189.

NGC225 is regular stop in the area since learning of it through Clark's book. He offers a list of open clusters that one can observe to estimate a telescope limiting magnitude (TLM). In the appendix of the book he provides two copies each cluster, one marked up with magnitudes and the other unmarked. One can find the same thing on the web at WEBDA. One can even interact with the cluster chart by changing chart parameters like V_mag.

The Saturday session's TLM was magnitude 13.2, on Sunday it was 12.6. At the time of Saturday's observation, Capella was rising above the tree line, her elevation about 10°. At mag 0 the difference in brightness is - what? Wow!

There's plenty more to see as we look over the galactic spur we're in across interarm space down onto the Perseus arm. The city sky from TotL does reveal an obvious Milky Way but through my optics the irregular nebulousity that glows softly, faintly, unmistakeably paints the background sky.

Thursday, September 14, 2006

still around...

...just been dormant.

Have been reading a good book: Voyage to the Great Attractor by Alan Dressler. I have read a couple of cosmology books in the past with some difficulty. This book has helped me [proto-}crystallize some of those hard to grasp concepts and realities. Dressler exhibits a poetic touch which I like when he describes different aspects of the world he interacts; he also has a knack for offering analogies to simpler, more everyday events or things that I am able to deliberate with a sense of understanding.